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Once your taxable revenue passes $30,000 over four consecutive quarters you must register for GST/HST and charge it. Many businesses register earlier to claim input tax credits. We handle registration and filing for you.

What is the difference between GST, HST and PST?

GST is the 5% federal tax. In HST provinces (Ontario and the Atlantic provinces) the federal and provincial portions are combined into one tax. BC, Saskatchewan, Manitoba and Quebec keep a separate provincial sales tax (PST, RST or QST) on top of the 5% GST.

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Corporate instalments

Corporate tax instalment calculator

Instalments catch profitable second-year corporations by surprise. Enter your tax owing to see whether they apply to you.

Net federal tax owing (highest of this year and the two prior years) Is this the corporation’s first tax year?

Eligible small CCPC with a clean compliance history?

Estimates for general information — not tax advice specific to your situation. Rates and rules change and your result depends on details a calculator cannot capture. We confirm the numbers for your circumstances in a free consult.

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The year-two surprise

A corporation pays no instalments in its first tax year. If year one is profitable, the CRA then expects instalments through year two — while you are also paying year one's balance. Owners who did not budget for the overlap feel it as a cash-flow shock rather than a tax increase, because that is what it is: the same tax, paid earlier.

Three ways to calculate — pick the lowest

The CRA permits the prior-year method (last year's tax, spread evenly), the current-year method (your own estimate of this year), and a two-year blended method. You may use whichever gives the smallest payments — but if you estimate low and are wrong, instalment interest applies to the shortfall, and it is not deductible. The current-year method suits a business you know is shrinking; the prior-year method is the safe default.

If you have already missed some

Instalment interest is charged, but it can be offset by paying later instalments early — the CRA applies a contra-interest calculation. Catching up promptly genuinely reduces the cost. The full instalment guide → or see the T2 deadline calculator for your filing and balance dates.

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Common questions

Corporate Tax Instalment Calculator FAQ

When does a corporation have to pay tax instalments?+

Generally when net federal tax owing exceeds $3,000 in the current year or in either of the two preceding years. A corporation in its first tax year is exempt.

Monthly or quarterly?+

Most corporations pay monthly. Quarterly instalments are available to an eligible small CCPC claiming the small business deduction with a clean compliance history — meaning no recent late filings or late remittances.

What if I pay too little?+

The CRA charges instalment interest on the shortfall at the prescribed rate, compounded daily and not deductible. Paying later instalments early can offset some of that interest.

Do provincial instalments work the same way?+

British Columbia’s corporate tax is administered by the CRA and collected together with federal tax, so a single instalment covers both. Quebec and Alberta administer their own corporate tax and have separate instalment requirements.

Want these numbers confirmed for your business?

A free consult with a Fraser Valley CPA — we will check the figures against your actual situation and quote a fixed fee.

Book My Free Consult Call (604) 832-1743